Update MTPROXY_CHECK_TIMEOUT to 45s in docker-compose and documentation; adjust default timeout handling in code for improved performance under slow network conditions.

cmd/mtproxy_checkerd/main.go

@@ -58,7 +58,8 @@ func loadConfig() (*config, error) {
 	}
 	timeoutStr := strings.TrimSpace(os.Getenv("MTPROXY_CHECK_TIMEOUT"))
 	if timeoutStr == "" {
-		timeoutStr = "15s"
+		// Fake-TLS + drain + req_pq/resPQ к DC часто >15s на медленных линиях и при многих прокси подряд.
+		timeoutStr = "45s"
 	}
 	checkTimeout, err := time.ParseDuration(timeoutStr)
 	if err != nil || checkTimeout <= 0 {